In the past, a technique of acquiring and transmitting an audio signal of a certain space using a large-scale microphone array and reproducing the same acoustic field in another space using a large speaker array has been introduced.
As a technique related to such acoustic field reproduction, a technique of reducing an operation amount when a speaker drive signal for outputting a sound through a speaker array is calculated by performing spatial frequency transform and diagonalizing a transfer function matrix has been proposed (for example, see Non-Patent Literature 1).
However, in a case in which the acoustic field reproduction is performed, if a sound that is not in an audio signal transmission source, that is, a sound collection space, such as a reflected sound in a wall, a ceiling, or the like, a reverberant sound, or the like occurs in a reproduction space in which an acoustic field is reproduced, spatial reproducibility of the acoustic field decreases, and a sense of presence is impaired. In the technique described in Non-Patent Literature 1, since an ideal spatial transfer characteristic in a free space is premised, the spatial reproducibility of the acoustic field may sometimes decrease depending on a reproduction environment.
The decrease in the spatial reproducibility of the acoustic field can be suppressed by measuring a spatial transfer characteristic of a sound including reflection and reverberation in a reproduction space and carrying out a spatial correction process.
As such a technique, for example, a technique of using an actual spatial transfer characteristic for a calculation of a speaker drive signal in acoustic field reproduction using a speaker array has been proposed (for example, see Non-Patent Literature 2). In this technique, the speaker drive signal is calculated by performing a time frequency transform on a measured spatial transfer characteristic from each speaker to an observation point (control point) and calculating a pseudo inverse matrix of a spatial transfer characteristic matrix for each time frequency.